Description The Chinook salmon, Oncorhynchus tshawytscha, is the largest species in the pacific (Oncorhynchus) salmon family. Other commonly used names for the species include King salmon, Quinnat salmon, Spring salmon and Tyee salmon. Chinook are an anadromous fish native to the north Pacific Ocean and the river systems of western North America ranging from California to Alaska. They are also native to Asian rivers ranging from northern Japan to the the Palyavaam River in the Siberian far east, although only the Kamchatka Peninsula supports relatively persistent native populations. They have been introduced to other parts of the world, including New Zealand and the Great Lakes. A large Chinook is a prized and sought after catch for a sporting angler. The flesh of the salmon is also highly valued for its dietary nutritional content which includes high levels of important Omega-3 fatty acids.

The Chinook is blue-green or purple on the back and top of the head with silvery sides and white ventral surfaces. It has black spots on its tail and the upper half of its body. Its mouth is often dark purple. Adult fish range in size from 33 to 36 in (840 to 910 mm) but may be up to 58 inches (1,500 mm) in length; they average 10 to 50 pounds (4.5 to 23 kg) but may reach 130 pounds (59 kg). The current sport-caught World Record is 99 pounds (45 kg) and was caught in 2002 in the Skeena River (Terrace, British Columbia). The commercial catch world record is 126 pounds (57 kg) caught near Rivers Inlet British Columbia in the late 1970s. In the Pacific Northwest, the especially large summer runs of Chinook that were once common (before dams and overfishing lead to declines) were known as June Hogs.

Dimensions Up to 4'10" (1.6 m); 126 lbs (57.2 kg).

Endangered Status The Chinook Salmon is on the U.S. Endangered Species List. The Sacramento River winter-run population in California is classified as endangered wherever it is found. Other naturally spawned populations in California, Idaho, Oregon, and Washington are classified as threatened. Why the Chinook and other Pacific Northwest salmon have declined is no mystery. The causes are known as "the four H's": harvest, habitat, hatcheries, and hydroelectric power. Harvest refers to the overfishing of these species by commercial fishing interests. Habitat refers to the degradation of habitat, usually by pollutants or sediment in the water that make it uninhabitable by the salmon or their eggs. Logging, agriculture, and mining interests have had a large hand in contaminating fish-run habitats. Captive-bred hatchery fish, released in the waterways used by native fish, compete and interbreed with the natives, weakening their stocks. Hydroelectric dams have had perhaps the largest impact, blocking migration routes and changing the quality, quantity, rate of flow, and temperature of the water in rivers, lakes, and tributary streams that once supported tens of millions of salmon.